Social psychology has tended to assume that the most effective means for reducing intergroup hostility is to breakdown social categories. This strategy is problematic, however, both because social categories are natural and useful perceptual tools, and because many group members want to retain their identity as part of their specific social group. We suggest that it may be possible under certain conditions for strong category boundaries and harmonious intergroup relations to simultaneously exist. This depends critically on the context or framing of how to think about group differences. We propose four sets of studies designed to explore two general goals. The first goal is to understand the nature of the relationship between category differentiation and intergroup evaluative bias. That is, we intend to explore the conditions under which these two constructs are and are not related, as well as the causal direction of the relationship. The second goal is to explore a multicultural ideological framing of social interactions as an alternative means for reducing intergroup conflict. A variety of methodologies are utilized including laboratory manipulations of ideological orientation, evaluation of naturally occurring ideological interventions, and a large scale survey assessment of a representative national sample. Knowing whether and under what circumstances such an intervention might be effective in combating prejudice and hostility would result in a substantial contribution both to social psychology and to society at large.